1. Field of the Invention
The present invention relates to systems for monitoring motor vehicle parameters, and more particularly to systems and methods for determining acceleration.
2. Related Art
Motor vehicles having navigation systems with route determining and tracking capabilities are generally widely available. Some systems may include features that assist the driver in conserving fuel by determining routes based on fuel efficiency. In one example, a navigation system may determine suggested routes having an estimated minimum fuel usage for a vehicle. The routes may be based on an estimated fuel efficiency of the vehicle, different speeds of the vehicle, and on estimated speeds for the route. The estimated fuel efficiency for the vehicle may also be based on aggregated data for the vehicle, or alternatively, on actual data for the vehicle.
Accurate fuel efficiency estimates for specific roads may be difficult to determine. Fuel consumption may depend on many different factors relating to the driver's route preferences and real-time route information, which includes current traffic conditions, current accident reports, weather information, current construction sites, and other similar data. Some implementations have addressed these constraints by estimating fuel usage based on actual driver behavior data.
Route determining systems may analyze the driver's behavior by determining, for example, whether a driver regularly speeds, accelerates fast, or drives in other ways that would expend more fuel than a typical driver. The route determining system may then use the data in estimating parameters associated with fuel expenditure.
In some implementations, route determining systems may infer road speeds and provide context-sensitive routing. Such systems assume road speeds to be functions of the properties or classes of roads (for example, two lane, four lane, expressway, state highway, or county highway), the area surrounding the roads (for example, commercial, residential, or agricultural), the terrain around the road, posted speed limits, nearby resources (for example, shopping areas, recreational parks, and other resources), and other suitable data. Other sources of information may also be used, including weather information, relationships among roads, road types, and traffic conditions, and special geometric relationships between types of roads (for example, the distance between a road segment from a freeway on-ramp or off-ramp). A limited set of sensed data may also be used to deduce road speeds. Statistical methods may be used to analyze the data relating to the road segments and the limited sensed data and to arrive at context-sensitive estimates of velocities on the road segments.
Route determination systems have implemented ways to increase the accuracy of fuel efficiency determination and other characteristics that may be affected by driver behavior, road conditions, time-related conditions, and other factors. Nevertheless, the potential for substantial inaccuracies remains. Conventional navigation systems typically use static parameters when determining and making use of fuel consumption estimates. Static parameters, such as, for example, distance, number of curves and maximum or average velocity, may not be sufficient to determine the fuel consumption of a car on a road segment, particularly in dynamically changing traffic situations.
There is a need for improvements in analyzing driving conditions to more accurately assess performance factors such as fuel consumption.